Dual rotation propeller



T. B. MARTIN ET AL DUAL ROTATION PROPELLER April 18, 1950 Original Filed Aug. 19, 1945 000 0 O Q 0 O o 0 U 0 INVENTORS THOMAS B.MART/N KENNETH l BERIWNGER Mu w lfl'fio ATTORNEYS w H s z N 0 \v v o a 0 0 mmw 3 e o e am h 7 an e m.

& s a q J 1. JG Q g a M Q Q Q 3 Q.

April 18, 1950 T. B. M RTIN HAL 2,504,559

DUAL ROTATION PROPELLER Original Filed Aug. 19, 1943 2 Sheets-Sheet 2 INVENTORS THOMAS 5. MART/N BY KENNETH L. BERN/NEE? ATTORNEYS Patented Apr. 18, 1950 UNITED STATES PATENT F F [GE DUAL ROTATION PROPELLER Thomas B; Martin'and Kennethnimrnmger,

Daytong-Ohio, assignors toGeneral Mo'tors Corporation, -Detrcit;-Mich., ar oorporation of Delawa re Original application August '19, '19'4'3,'Serial No.

499,240. Divided and thisfapplication Februat? 7, 1946, Serial N0. 64:6;156

4' Claims.

l -h4s'-invention'=relates to aircraft propellers of the ta'ndem type in which two completezpropelfer-assemblies, rotate in opposite directions, and

control mechanism and hub fairing means or sprsnerywnh built-in anti-icing means, wherebv 'mounting on a drive shaftobviates the'ne'ce'ss'ityof linkage and levers with complicated adjustments.

'Ye'tanother object is to'provide a dualrotamm propeller with hub fairin that will preserve thestreamlining of the craft, yetnot require excessive time and technicians for installeZtion.

Gon tributing'to the principal or foregoingobfacts is the object to provide anti-icing means for both propeller assemblies, and to protect the delivery of an anti-icing medium against dispr'sion until delivered at' the root of the intended blade.

="Another object of the invention is to provide spinners for coaxial counter rotating propeller assemblies-and means for supporting the spinners so that thestreamlined continuity of the fuselage will be maintained.

iknother object of the invention is to provide spinners for enclosing the hubs of aircraft propellersand mount them on shock absorbing supportshaving a greater resistance to vibration in animal direction than in a circumferential dire'ctfen.

Fur ther obiects and advantages of the present invention will be apparent from the following description, re'ference being had to the accompat-lying drawings wherein preferred embodimeiits ofthe-present invention are clearly shown.

=Inthe drawings:

*Figi I i a side elevational view of a dual-rotationpropell'er'with spinner parts in section-for Ffg-sL- 3, 4 a'nd'5are detail views'of the outboard spinner 'mounting.

Referring generally to the drawings and" specifically with respect to Figs. 1, and 2, l0 refers tothe engine-nose or gear-casing of an aircraft fromwhich projects in rotative relation a pair of oppositely rotating telescopically arranged shafts. Mounted on the radially outer shaft is an'inboai'd propeller unit 16 comprising a hub lt fitted with adesired number ofcontrollablepitch blades 20 extending from blade socket 2-2. Mounted on the radially inner shaft-is'an outboard-propeller nnit 24* comprising a hub -2 S- fitte'd with-adesired number of controllable pitch-blades 28 eiitending from sockets 30. Both "p1'opeller unit's -a're provided with individual automatic pitoh controlling mechanism built-in as self-contained units, so that one propeller and its controt-mechanism may be mounted on the shaft l2 'and the other propeller and its control mechansm may be mounted on the shaft M, simply by moving" the units respectively in place on their shafts and tlien securing with appropriate shaft nuts. '-In so "doing, an interconnecting mechanism-32 situated between the hubs l8 and 26 appropriately connects the control mechanism of one' pro'peller unit with the control mechanism of the other propeller unit as will be described in due conrse. Suflice it then, here, to say, that the inboard-nub 18"With its'blades 20, is afiixed with a cont'rol unit or regulator 3'4, andsupports a spinner-section 36 suitable to be mounted on theshaft l2 adiac'ent to the engine nose l0, and provides a part of the interconnecting mechanism 32,-at'its forward end. And likewise, the outboard hub '25 w th its blades 23 and affixed with a control or regulator-38, supporting a spinner section 40, is also provided with a cooperating part of the interconnecting mechanism 32, and ismountableo'n the shaft [4.

Tl-iespinner sections 35 and '40 are each substantially generated conic portions designed to blendin with"the nacelleof the craft and provide proper fairing-for the'hubs so that stream lining'of -the craft is preserved from the air piercing portion atthe'axis of the propeller shaft throughout the length ofthe craft. Contributing toward that, the spinner section of the inboard propeller It comprises a truncated c'onicport-ion, ofsheet metal or the like. provided'with a flange or head portion-42 at its smaller end that-isadaptd-to be fastened to the front end of the hub provide ledges for reception o'f'filler plates whieh span "the cutouts -46 Y and where they are- The notches '46 are reinforced with 3. secured by quickly detachable fasteners 52. Attached to the inside of the spinner shell 36 and near the base end there are webs 54 and 56 which, as the spinner is moved inwardly, engage supporting pilot pins 58 positioned around the periphery of the regulator 34. Thus, when the spin ner section is mounted in place, the base end of the spinner projects aft far enough to extend over the end of the engine nosing I0, while its forward end projects sufficiently far enough ahead of the propeller disc of rotating blades to end in an offset portion 60 outwardly of the interconnecting mechanism 32.

The spinner section 40 for the outboard propeller comprises a generated cone inside of'which there is fastened a head-member 62, and web portions 64, 66 by which the section is similarly supported on the hub 26 and regulator 38. To this end, the web portions 54, 56 and 64, 66 are secured at their radially inward bounds to plates or clips 85 by screw devices 61, the plates 65 in turn being secured to the boundary of the regulators 34 or 38 by the screw devices 69 holding the parts of the regulators together. It, like the section 36 for the inboard propeller is slidable over the hub and blade roots to engage the pilot pins, but is ad ditionally characterized by holding means in the form of a rod 68 anchored to the hub 26. A cover plate 69 covers the head of the rod 68 where it is held by a spring lock at the air piercing end of the cone. The section 40 is similarly notched at 46 and the unoccupied portions are filled in by the plates 50, all so that the base end of the generated cone 48 may overlap outward of the offset portion 60.

Vibration absorbing means are adopted for supporting the spinner sections 36 and 46 and incor porate the Structure as shown in Figs. 3 and 4. The circumferentially inner flange of the respective heads or webs 62, 64, 54 and 56 are apertured to receive a flanged bushing H which is peened over at 13 for retention purposes. The bushings H are of considerably larger bore than the studs or pilot pins 58 over which they are to be dis posed, and bonded to the inside of the bushing there is a crescent shaped piece of yieldable material such as rubber the inner arc of which is bonded to a short length of tube 11 having its edges staked at 19 to engage the inner periphery of the bushing ii. The tubular portion 17 has a bore substantially commensurate with the cross section of the pilot pin 58, or such that the two may be engaged in easy slidable engagement. Thus the pilot receiving portion of the anchorage is to one side of the center of the bushing H, and in mounting the bushing within the spinner supporting web or head, advantage is taken of this offset relation to absorb the load of the clamping thrust in mounting. To accomplish that, the bushing is so located that the widest portion of the rubber body will be disposed radially outward of the pilot pin so that any inward flexing 0f the spinner shells will tend to compress the rubber section, while the lateral movement of the same may be permissible for absorption of vibration. That presents a structure in which radial outward movement of the spinner sections with respect to the pilot pins will be restrained because of the firm metallic contact or engagement on the pilot pins yet circular oscillations about the axis of propeller rotation will be permissible. That is particularly accounted for by providing the voids 8 I in the rubber in the region of tube and bushing engagement substantially as shown in Fig, 3.

An alternative vibration absorbing mount is shown in Fig. 5, where an angled bracket is secured to the inner periphery of the webs 64, 66 bya pivot 81 and a screw device 89 having a rubber or like bushing 9| to absorb the .vibration. The other leg of the angled bracket is receptive of the pilot pin 58 carried at the rim of the regu- Thus in mounting the spinner sections, with the cover plates 50 removed, they are passed over the hub portion so that the notches 46 straddle the blades and so that the vibration supporting means each engage a pilot pin 58. In the case of the inboard propeller the forward portion of the spinner section 36 is secured to the hub I8 by the screw devices 44. In the case of the outboard propeller the spinner section 40 is passed over the blades until the vibration absorbing means engage the pilot pins 58 both in the regulator 38 and on the front portion of the hub where the forward spinner section is retained in position by the rod 68. The rod 68 threads into a plate in the fore.- ward end of the hube 26 and springs a, bridge piece 82 whose outer extremities engage the inner pe riphery of the head member 62 to force itv into. seating relation against the hub face plate. With is made for conducting anti-icing fluid to the; roots of the blades from a suitable reservoir andincludes the transmission tubes 74 and I6 dis-i posed to empty into a pair of slinger grooves 18.

and 80 in a rotating part of the inboard propeller structure. As illustrated in Fig. 2, the slinger groove 80 connects with delivery tubes 82 that slant outwardly and curve around the root of the blades 20 to end at a point near the leading edge;

of the respective blade, such as indicated at 84 Connecting with the slinger groove I8 a crosspassage 86 through the regulator 34 communicates with a transmission tube 88 slanting outwardly so.

tubes 92 lead out to points 94 near the leading edge on the blades of the outboard propeller.-

When the propeller mechanism is rotating theanti-icing medium delivered by the tubes 14 and 76 empties into the grooves 18 and 80 from whence, by the outward inclination of the connecting passages, the medium is delivered to the roots of the blades on the inboard propeller and.

to the groove of the outboard propeller, .and

thence to the roots of the blades of the outboard. propeller. The ends of the tubes l4, l6 and 86 no opportunity for wind and rapidly moving air currents is afforded to carry away the fluid before it reaches the desired points of delivery. However, due to the design and support of the spinner structure, all connections of the fluid passages for the anti-icing medium are enclosed well within the confines of the spinner where the wind and air movement will have little effort upon openjunctures of the passages.

While the embodiments of the present invention as herein disclosed, constitut preferred formsfit is to be understood that other forms might'be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. An aircraft propeller installation, comprising in combination, a pair of concentric contrarotative propeller shafts extending from an engine nosing, a pair of propellers, each comprising a hub and pitch shiftable blades mounted on the said shafts, a spinner section of conic form for each hub, means for mounting each section on its hub, including a bulk-head, braced web portions, pilot pins on the hub for supporting the web portions, and vibration absorbing means carried by the web portions for seating on the pilot pins, and positive retention means for securing the head members to the hubs, the spinner section for the outboard propeller having an air piercing cone with a base portion fairing in with the contour of the rear section and a rod axially connecting the apex of the cone to the hub of the outboard propeller for retaining the spinner on the pilot pins.

2, An aircraft propeller installation, comprising in combination, a pair of concentric contrarotative propeller shafts extending from an en-- gine nosing, a pair of propellers, each comprising a hub and pitch shiftable blades mounted on the said shafts, a spinner section for each hub mounted to rotate therewith, means for mounting each section on its hub including web portions extending radially inward to engage the hub, pilot pins carried by the hub, and rubber filled grommets at the inner bounds of the webs receivable over the pilot pins, said grommets comprising a flanged bushing secured in the web and having a relatively large opening, a sleeve adapted to slide over one of the pilot pins and disposed within the opening of the bushing eccentric of the said large opening, and yieldable material bonded to the inside of the flanged bushing and to the outside of the sleeve to maintain the eccentric relation, and. means securing the grommet in the web so that the yieldable material is disposed radially outward of the respective pilot pin when the spinner is mounted on the hub, whereby vibration and load forces transmitted to the spinner sections from the hub are damped, and means for securing the spinner sections in their piloted relation,

3, An aircraft propeller installation, comprising in combination, a pair of concentric contrarotative propeller shafts extending from an engine nosing, a pair of propellers, each comprising a hub and pitch shiftable blades mounted on the said shafts, a spinner section for each hub mounted to rotate therewith, means for mounting each section on its hub including web portions extending radially inward to engage the hub, pilot pins carried by the hub, grommets carried by the web portions surrounding the pilot pins and provided with sleeves eccentrically located on the grommets for frictionally engaging the pilot pins, and yieldable rubber like cushions between the grommets and sleeves and bonded thereto, said grommets locating the cushions radially outward of the axis of propeller rotation, whereby gyrational forces are substantially eliminated, and means for securing the spinner sections in their piloted relation on the respective hubs.

4. An aircraft propeller installation, comprising in combination, a pair of concentric contrarotative propeller shafts extending from an engine nosing, a pair of propellers, each comprising a hub and pitch shiftable blades mounted on the said shafts, a spinner section for each hub mounted to rotate therewith, means for mounting each section on its hub including web portions extending radially inward toward the hub, angled brackets secured to the extended web portions to pivot thereon at its angle, one arm of the bracket being secured to the web by a pin and yieldable bushing for limited oscillation, the other arm of said bracket extending radially inward to overlap a portion of the hub, pilot pins carried by the hub for engaging apertures of the said overlapping bracket arm, whereby gyrational forces transmitted to the spinner are damped, and radial movement due to centrifugal forces are substantially eliminated.

THOMAS B. MARTIN. KENNETH L. BERNINGER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,129,565 Clay Sept. 6, 1938 2,353,578 Marshall July 11, 1944 2,375,673 Marshall May 8, 1945 2,421,514 Martin et a1 June 3, 1947 FOREIGN PATENTS Number Country Date:

832,913 France Oct. 6, 1938 539,880 Great Britain Sept. 26, 1941 544,425 Great Britain Apr. 13, .1942 554,453 Great Britain July 5, 11943 

